ROME - Italy's rival populist leaders sought more time Monday to hash out a deal to govern together, with one side citing significant differences over how to stop the flood of migrants coming in and the other insisting his supporters have their say online before finalizing any coalition deal.

Blunt-talking Matteo Salvini, who heads the right-wing anti-migrant League party, indicated he'd prefer to go to a new election, 10 weeks after a vote yielded political gridlock, if his forces don't get a "free hand to manage the security of Italians." He was referring to the large numbers of migrants coming into Italy whom many in the country blame for crime.

But Luigi Di Maio, leader of the populist 5-Star Movement, sought to put a more positive spin on their talks. The 5-Stars, which bills itself as an alternative to traditional politics, makes its positions and candidates subject to review by supporters in online votes.

Coalition negotiations are aimed at "giving a government of change to this country," Di Maio said, insisting on more time to achieve a deal so the coalition could last the five full years of Parliament's term.

Any deal "will be put to our members through a vote online," Di Maio said.

Both men spoke to reporters at the presidential Quirinal Palace in Rome, where President Sergio Mattarella had summoned them for an update on their negotiations.

Mattarella has said if political leaders can't form a coalition he'll appoint a non-political person to lead Italy to an early election by year's end.

With neither Di Maio nor Salvini willing to cede the premiership to the other, they need to find someone else palatable to both of them whom Mattarella could tap to form the next government. But both said they haven't gotten to that point yet.

Justice issues are important to Italy's scandal-plagued former premier, Silvio Berlusconi, whose Forza Italia party was part of a centre-right campaign alliance with the League that captured 37 per cent of the March 4 vote, making it Parliament's largest bloc.

"We don't want to split the centre-right alliance," Salvini said.

"If we're good enough to find the solution, we'll get started (with a government) without problems, but we don't want to take the president and the Italians for a ride," Salvini said, citing the differences still remaining.

Berlusconi had promised his party's voters quick deportations for the hundreds of thousands of migrants who are ineligible for asylum.

Di Maio's 5-Star Movement is Parliament's single biggest party, after winning some 32 per cent in the March 4 election.

Forging a coalition would put the 5-Stars in Italy's national government for the first time. It would also be Italy's first all-populist government.

Berlusconi has refused to govern with the 5-Stars, who he regards as "more dangerous than communists."

The League's support largely is centred in northern Italy, where it backs lower taxes and reining in central government spending, a popular platform in Italy's most productive region.

The 5-Stars strongly appeal to voters in the south, where youth unemployment runs higher than 50 per cent in many areas. Di Maio has pledged to guarantee a minimum income to the unemployed.

The opposition Democrats have warned that the League's vow to drastically lower taxes to a flat 15-per cent rate and the 5-Stars' promise of subsidies to the poor will drastically drive up government borrowing.

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